Mobile device battery



FIG. 1 is a top plan view of a mobile device battery showing our new design;

FIG. 2 is a elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof; and,

FIG. 5 is a bottom plan view thereof.

The broken lines shown in FIGS. 1–5 are included for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a mobile device battery, as shown and described. 